Electric frequency-transforming device



Sept. 19, 1933.

J. VAN DER MARK El AL 1,927,425 ELECTRIC FREQUENCY TRANSFORMING DEVICEOriginal Filed May 29 .1928

5) THE/R ATTORNEY (9:1! 44 Patented Sept. 19, 1933 UNITED STATES PATENTOFFICE ELECTRIC FREQUENCY -TR.AN SFORMING DEVICE Application May 29,1928, Serial No. 281,468, and-in Great Britain June 14, 1927. RenewedJanuary 30, 1932 11 Claims.

The present invention is concerned with a frequency-transformer of thestationary type and has for its object to provide an apparatus of thisclass which, under the influence of incoming primary electricoscillations, is adapted to generate secondary oscillations at afrequency which will be lower than thefrequency of the incomingoscillations.

The object of the invention is to provide means by which the ratiobetween the frequency of the primary and that of the secondaryoscillations may be readily adjusted.

The invention will be more fully described with the aid of theaccompanying drawing. Figure 1 shows graphically how the primaryoscillations are de-multipled. Figure 2 is a schematic showing of thedevice according to the invention. Figure 3 shows graphically thefrequency of the relaxation oscillations plotted against the naturalfrequency of the primary oscillations.

According to this invention, the primary oscillations control thevibrations in a circuit containing a condenser and a resistance, eitherof which or both of which can be made variable, and a gap across whichthe condenser may discharge itself when the potential difference betweenits electrodes has reached a predetermined value owing to its beingcharged through the said resistance by a battery or other suitableconstant potential source. Oscillations set up in this way, which may becalled relaxation oscillations", will have a time period which is alinear function of the product of the capacity C of the said condenserand of the value R of the said ohmic resistance, as is well known in theart. (See e. g. Philosophical Magazine, November, 1926.)

When the alternating potential of the primary oscillations of afrequency W0 is superimposed upon the direct current voltage between theplates of the condenser, the latter will be charged in the waygraphically shown in Figure 1 of the drawing accompanying thespecification, in which the tension V between its plates is plotted as afunction of the time. As soon as V attains the value V0, the condenserwill suddenly discharge across the above-said gap, which, for instance,may be the interelectrodic space of a glow discharge lamp, whereupon thecondenser will again be charged in the manner described and soon. Fromthe diagram of Figure 1, it will whole submultiple of W0.

be clear that each charging period will correspond with a plurality ofprimary oscillations, say 11. full waves, which makes the frequency W ofthe relaxation oscillation equal to Since n will depend upon thesteepness of the curve a in Figure l which shows the unidirectionalpotential between the condenser plates as a function of time; and sincesaid steepness may be varied at will by varying either or both of thevalues- R and C, it will be obvious that W may also be given practicallyany desired value being a The consecutive discharges of the condenserwill occur at such points of the combined voltage curve as are in aphase with each other with regard to the primary oscillations whichmeans that there will be always a whole number of full primaryoscillations between each two discharges of the condenser. Consequently,when the steep- I ness, of the curve a is varied gradually, the value ofthe resulting frequency W will vary discontinuously. It is thus possibleto obtain relaxation oscillations, the frequency of which amounts to /2,A, A etc. of the frequency of the primary source.

Figure 2 is a diagram of connections showing an embodiment of theinvention. A source 1 of an alternating electromotive force of asuitable amplitude is connected in series with a glow discharge lamp 2and a variable condenser 3. In parallel to the condenser 3 a battery 4and a resistance 5 are put in series with each other. Condenser 3 ischarged by battery 4. through resistance 5, the alternating potential ofthe source 1 being superimposed upon the direct current potentialbetween the plates of condenser 3. The latter will periodicallydischarge itself through the glowlamp 2.

When the capacity of the condenser 3 is varied gradually, say from itsminimum to its maximum value, the frequency of the relaxationoscillations which initially amounted to say A WO, will remain unchangedfor some time and then when the natural relaxation-frequency of the R. Ccircuit is closer to Wo than to M WO will suddenly fall to /;;W., and soon. This is graphically shown in Figure 3, where the frequency W of therelaxation oscillations is plotted against the natural frequency We ofthe primary oscillations.

It will be obvious that the invention is not confined to the use of aglowlamp for the gap across which the condenser may discharge itself,but that other devices, such as, for instance, electron discharge tubesof various design may be used instead, without departing from theinvention.

What we claim is:

1. A circuit arrangement for de-multiplying electrical oscillations,comprising-a source of primary oscillations in series with a path ofdischarge, a condenser, a resistance, and a source of direct current,the resistance and the source of direct current being connected inseries with the source of primary oscillations and the path ofdischarge, and the condenser being connected in parallel across theresistance and the source of direct current.

2. A circuit arrangement for producing whole sub-multiples of electricaloscillations comprising a source of oscillations in series with a pathof discharge, a condenser, an impedance, and a source of uni-directionalcurrent, the impedance and the source of direct current being connectedin series with the source of oscillations and the path of discharge, andthe condenser being connected in parallel across the impedance and thesource of direct current, said condenser being adapted to periodicallydischarge across said path to produce a frequency lower than thefrequency of said source of oscillations.

3. A circuit arrangement for producing whole sub-multiples of electricaloscillations comprising a path of discharge, a condenser, an impedance,said condenser and said impedance being connected in parallel acrosssaid path of discharge, a source of primary oscillations and a source ofunidirectional current associated with said condenser, both said sourcesbeing arranged to impress currents simultaneously upon said condenser,said condenser being adapted to periodically discharge across said pathat predetermined intervals to produce a current of a frequency lowerthan the frequency of said source of primary oscillations. a

4. A circuit arrangement for' demultiplying electrical oscillationscomprising a glow discharge device, a circuit comprising a reactance, animpedance and a source of uni-directional potential connected with saidglow discharge device, and a source of primary oscillations connected tosaid circuit and said' device, both said sources being arranged to actsimultaneously upon said reactance to cause said arrangement tooscillate at discrete frequencies determined by whole submultiples ofthe applied frequency.

5. A' circuit arrangement for demultiplying electrical oscillationscomprising a space discharge device, a source of potential in seriestherewith, a series combination of a variable condenser and a resistanceconnected across said source of potential, and a source of primaryoscillations coupled to said device and said series combination, bothsaid sources being arranged to act simultaneously upon said device andcondenser to produce oscillations of a frequency lower than thefrequency of said source of primary oscillations.

6. A circuit arrangement for sub-dividing electrical oscillationscomprising a source of primary oscillations, a source of uni-directionalcurrent,

a space discharge and a resistance element connected in series one withrespect to the other and forming together a closed electrical circuit,and a condenser upon which the currentsfrom both said sources aredirectly impressed connected in parallel with a portion of said circuitto divide the circuit into two parts each including one source so thatthe source of primary oscillations is adapted to alter the naturalcharging period of the condenser to vary thereby the normal oscillationfrequency of the system.

7. A frequency demultiplication system comprising a relaxationoscillator circuit including as a part thereof a gaseous dischargedevice, a source of direct current and an energy storing element tocontrol the time period of operation thereof, and a source of appliedoscillations of a frequency other than the normal oscillation frequencyof ,the system connected with the oscillator circuit so as to actsimultaneously with the direct current upon the storing element andthereby to cause the element to discharge through the discharge deviceperiodically at a frequency which is a whole sub-multiple of the appliedfrequency, said discharge frequency being equal to 1 where W0 is equalto the frequency of the applied oscillations and N is equal to anydesired number of full waves.

8. An oscillation circuit comprising a series combination of a dischargedevice, an impedance and a source of unidirectional current and 9.capacity element connected in parallel with a portion of the seriescombination so as to control in accordance with the capacity valuethereof the natural oscillation frequency of the combination, and. meansfor supplying in series with the discharge device an alternating currentvoltage so as to vary thereby the natural oscillation'frequency of thesystem.

9. An electrical circuit comprising in combination a relaxationoscillator circuit having a predetermined natural oscillation frequency,and means to impress alternating currents upon the oscillator circuit ofa frequency other than the normal oscillation frequency to cause theoscillator circuit to produce oscillations at a frequency other than itsnormal frequency.

10. An electrical circuit comprising in comblnation a relaxation glowdischarge oscillator circuit having a predetermined natural oscillationfrequency, and means to impress alternating currents upon the glowdischarge oscillator circuit of a frequency other than the normaloscillation frequency to cause the oscillator circuit to produceoscillations at a frequency other than its normal frequency.

11. In an electrical generator system, a relaxation oscillator includinga space discharge ele- .ment, a source of unidirectional current and animpedance element serially connected and a capacity element to controlthe natural oscillation frequency connected in parallel with a portionof the series combination, and means for impressing upon the seriescombination alternating current voltages at a frequency other than thenormal oscillation frequency of the relaxation oscillator so as to causethe frequency of the generated oscillations to vary under the control ofthe supplied alternating currents.

JAN VAN DER MARK.

BAL'I'HAZAR van on POL.

